This invention, in general, relates to occupancy detection. More particularly, this invention relates to determination of class, attributes, and identity of an occupant in an occupancy space.
Occupancy detectors are typically used for lighting automation and in burglar alarms. Conventional occupancy detectors may, for example, be passive infra-red sensors or Doppler effect sensors. Passive infra-red sensors sense lateral motion across the field of view of the sensors but are generally insensitive to motion in line with the field of view. Doppler effect sensors sense motion in line with the field of view but are generally insensitive to lateral motion across the field of view. Hybrid sensors utilize both passive infra red sensors and Doppler effect sensors but are significantly expensive.
Typical passive infra red sensors and Doppler effect sensors are deceivable by minimizing motion within the fields of view of the sensors. Furthermore, typical sensors are unable to distinguish between human occupants and other mobile animate occupants and inanimate occupants. Typical sensors are also unable to detect stationary occupants of an occupancy space, thereby causing errors in detection.
Some limitations of passive infra-red sensors and the Doppler effect sensors may be overcome by using imaging based sensors. However, these sensors typically run at full power during operation, thereby consuming a high amount of energy, rendering them unsuitable for battery powered operation.
Hence, there is a need for determining the class, attributes, and identity of an occupant in an occupancy space at a predefined time, or on the occurrence of an event, or at periodic intervals and for distinguishing between animate human occupants and other occupants, irrespective of the state of rest or of motion of the occupants.